We all move when we sleep. Some people move more than others. It is not unusual for a person to have one or two jerking movements of the legs, arms, or whole body when just falling asleep. These are normal events and may happen every night or not at all. We call these jerking movements “sleep starts” or “hypnic jerks”.
Most people change position during sleep, changing from back to side, side to side, onto the stomach, etc. People sometimes awaken or can be totally unaware of these movements. Pain from any source can devastate sleep. Back, knees and shoulders lead the list, but pain in any part of the body can disrupt sleep and lead to movement. A normal change in sleep position can trigger pain and disrupt sleep, causing additional movement.
While moving during sleep is normal, some movements are not normal and some normal movements can occur excessively. These abnormal movements and excessive normal movements are sleep disorders. As a result of these disorders a person may experience poor quality sleep, discomfort, injuries and daytime symptoms. When it is suspected that a person is experiencing a sleep movement disorder, a polysomnogram is often required to identify the type of abnormality and its severity. Some of the common sleep movement disorders seen during a polysomnogram are described below.
Restless Legs Syndrome
Restless Legs Syndrome is a condition that causes uncomfortable sensations in the muscles, primarily in the legs, and is relieved by moving. Symptoms typically begin late in the day gradually becoming more intense throughout the night and resolve after a night of sleep. This condition makes sleep onset difficult and can be a cause of significant insomnia.
Periodic Limb Movements
Periodic limb movements (PLMs) are recorded in about half of the sleep tests performed at The Sleep Center. PLMs are rhythmical contractions of muscles in the extremities, primarily the legs. In order to be categorized as PLMs, the movements must meet standards of type of contraction, electrical strength, frequency and duration.
PLMs vary from rare and weak to frequent and strong. They may result in disruption of sleep. The disruption can be severe and result in many symptoms such as frequent nighttime awakenings and daytime sleepiness. When a person experiences symptoms with documented PLMs, the condition is called Periodic Limb Movement Disorder.
Sleep Walking and Talking
Walking and/or talking during sleep are not uncommon occurrences during childhood. These occurrences become less frequent with maturity and usually disappear. There are times when there are reasons to be concerned about these activities during childhood and certainly if they persist into adulthood.
REM Behavior Disorder
REM Behavior Disorder can be described as a person physically acting out their dreams while asleep. It occurs during the portion of sleep that we associate with dreaming, Rapid Eye Movement (REM) sleep. A person with this problem will often injure themselves or their bed partner by punching and kicking. Nighttime awakenings and daytime sleepiness are symptoms associated with this disorder.
Seizures can occur during sleep and sometimes only occur during sleep. Seizures result in movement. Depending on the portion of the brain affected by the seizure, the movements may appear normal, resemble movements seen with other sleep disorders, appear to be typical seizure movements, or are strange and unique movements.